The disclosure relates to ceramic coatings. More particularly, the disclosure relates to substrate preparation for ceramic coatings.
Components that are exposed to high temperatures, such as a component within a gas turbine engine, typically include protective coatings. For example, components such as turbine blades, turbine vanes, blade outer air seals (BOAS), and compressor components (e.g., floatwall panels) typically include one or more coating layers that function to protect the component from erosion, oxidation, corrosion or the like to thereby enhance component durability and maintain efficient operation of the engine.
As an example, some conventional turbine blade outer air seals include an abradable ceramic coating that contacts tips of the turbine blades such that the blades abrade the coating upon operation of the engine. The abrasion between the outer air seal and the blade tips provide a minimum clearance between these components such that gas flow around the tips of the blades is reduced to thereby maintain engine efficiency. Over time, internal stresses can develop in the protective coating to make the coating vulnerable to erosion and spalling. The outer air seal may then need to be replaced or refurbished after a period of use.
Similarly, the turbine blades may have an abrasive tip coating which properties are chosen to abrade the BOAS abradable coatings.